Romney appeared to win most of the state's southern and central region, while Gingrich's support was concentrated in the north.

The former Massachusetts governor snapped back from a loss in South Carolina with a Florida primary victory that took advantage of a more diverse electorate, re-established his image of electability and economic leadership and demonstrated his organizational firepower in attracting – and retaining – early-deciding voters.

His debate performance last week and negative ad campaign against chief rival Gingrich also played a key role in his victory in the Sunshine State. Behind the scenes, conservatives expressed concern that the often-personal attacks would fracture the Republican Party, but tonight, an upbeat Romney dismissed that idea.

"A competitive primary does not divide us. It prepares us," he said to cheers. "And when we gather here in Tampa seven months from now for our convention, ours will be a united party with a winning ticket for America."

Gingrich, however, gave no indication of backing off.

"It is now clear that this will be a two-person race between the conservative leader Newt Gingrich and the Massachusetts moderate," the former House speaker said today. "We are going to contest every place and we are going to win."

Surrounded by signs reading "46 States To Go," Gingrich indirectly jabbed Santorum -- who he has publicly said should drop out -- and vowed to fight as the conservative alternative to Romney.

"It is now clear that this will be a two-person race between the conservative leader Newt Gingrich and the Massachusetts moderate," the former House speaker said in an indirect jab at Santorum, surrounded by signs reading "46 States to Go."

"We are going to contest every place and we are going to win," he said, vowing to fight as the conservative alternative to Romney.

Romney jumped into Florida well before any of his competitors, launching TV ads even before the South Carolina primary. That move may have helped him, as exit polls found that far fewer Florida voters made up their minds in the Florida campaign's closing days than in any previous GOP contest this year.

Preliminary exit polls found that Republican voters were heavily influenced by the debates and campaign ads that dominated the Florida airwaves for weeks. As in Iowa and South Carolina, voters were looking for the candidate who has the best chance to defeat President Obama.

But there was also skepticism among voters about whether the former governor is conservative enough -- a substantial 41 percent of Florida voters described Romney's positions on the issues as "not conservative enough" and nearly four in 10 voters said they'd like to see someone else run for the nomination.

Both candidates and the super PACs supporting them have spent millions of dollars in attack ads, but the former House speaker was far outweighed by his chief rival when it came to spending.

Romney's campaign spent nearly $7 million on television ads leading up to the primary, more than six times that of Gingrich, whose campaign spent about $1 million.

The super PACs have even outspent the campaigns. The group supporting Romney, Restore Our Future, spent a whopping $8.5 million on ads in Florida, while Winning Our Future, the super PAC backing Gingrich, spent about $2.2 million.

Neither Rick Santorum nor Ron Paul, the other two candidates in the race, are on the airwaves. Both were instead focusing on Nevada, the next voting state.

Santorum today showed no sign of dropping out, saying that he, not Gingrich, should be the conservative alternative to Romney because he has less "personal baggage."

"This race can change on a dime," Santorum said at a Tea Party event in Las Vegas.

Paul expressed optimism about the upcoming caucus states and railed against the idea of the United States being the "policeman of the world."

"Send only people to the White House who know and read the Constitution and enforce the Constitution," he said to applause.

Romney was actually on the airwaves more in 2008, when he lost the state to Sen. John McCain. But in this race, he dominated the airwaves against his rivals, airing almost 13,000 ads on broadcast television across the state, as of Wednesday, Jan. 25 -- much more than Gingrich and his support groups, which together have aired about 200 spots, according to the Wesleyan Media Project.

Ninety-two percent of all TV ads aired in the Sunshine State over the last week were negative, mostly targeted at Gingrich, according to Kantar Media Campaign Media Analysis Group.

Gingrich had made his mark by stellar debate performances that set him apart from other candidates. It was one of the reasons why he won by an overwhelming margin in South Carolina. But that changed last week as Romney aggressively attacked Gingrich on his past connections to Freddie Mac and his immigration ads.

Fifty delegates are at stake in today's primary, an important number for Romney.